A typical case of a girl >25 kg who received an initial dose of 5 mg twice daily of Janus kinase inhibitor (JAKi) but required the maximum dose of 7.5 mg twice daily. She received this dose for 6 months, and the dose was gradually tapered. In the meantime, glucocorticoids were also tapered, and the patient showed an increased growth rate. (A) The typical skin lesions before treatment with JAKi. (B) Those lesions had mostly disappeared after treatment.

Background This study aimed to analyze the effects of ruxolitinib on children with secondary hemophagocytic lymphohistiocytosis (HLH). Methods Eleven pediatric patients diagnosed with HLH and treated with ruxolitinib (ruxolitinib group: group R) between November 2017 and August 2018 were retrospectively analyzed. Eleven age-matched pediatric patients with HLH undergoing conventional treatment (control group: group C) during the same period were also analyzed. Results In group R, three patients who did not respond to methylprednisolone (MP) pulse and intravenous immunoglobulin (IVIG) therapies were treated with Ruxolitinib and their temperature decreased to normal levels. Four patients had normal temperature after conventional treatment (dexamethasone and etoposide, with or without cyclosporine A), but they had severe organ involvement, including obvious yellowing of the skin, increased liver enzyme levels and neuropsychiatric symptoms, and they were all ameliorated with ruxolitinib treatment. Four patients were relieved with ruxolitinib therapy alone. In group C, the body temperatures of eleven patients decreased to normal levels after conventional treatment. The body temperature of group R patients decreased to normal levels more rapidly than that of group C patients. The glucocorticoid dosage in group R was significantly lower than that in group C. Both groups were followed-up for 2–2.5 years. No obvious adverse drug reactions to ruxolitinib were observed during treatment and follow-up. Conclusion Ruxolitinib might be an effective drug in controlling body temperature and reducing inflammation indicators. It might be a potential replacement for glucocorticoid therapy for HLH treatment in children, thereby reducing or avoiding glucocorticoid-related adverse reactions.

Background. Juvenile dermatomyositis (JDM) is a rare and sometimes fatal disease in children. The subtype of anti-NXP2 antibody-associated JDM is the leading cause of death in JDM, but there are no reports about clinical characteristics and high risk factors of poor prognosis. For the first time, we introduced the clinical characteristics and poor predictors of anti-NXP2 antibody-associated juvenile dermatomyositis in Chinese children.Methods. Twenty-six patients with anti-NXP2 antibody-related JDM from 85 JDM patients diagnosed from January 2016 to November 2019 were involved. Logistic regression was used to analyze the risk factors for refractory cases and death.Results. The ratio of male to female was 9:17. The median age of onset was 4.5 (1–13) years. Twenty-four cases (92.3%) had rash and muscle weakness. Treatments included glucocorticoids, immunosuppressive agents, biological agents (7 cases), plasma exchange, Janus kinase inhibitor (7 cases) and autologous stem cell transplant (1 case). Eleven cases (11/26, 42.3%) were refractory JDM associated with edema, skin ulcer, muscle strength < = grade 3, CD4/CD8 ratio < 1.4 and SF > 200ug/ml. Among 6 cases (6/26, 23.1%) with severe gastrointestinal involvement, 5 cases died and 1 case survived after ASCT. The risk factors for gastrointestinal involvement and death were edema, skin ulcer, severe muscle weakness (Dysphagia/Hoarseness/Lower voice), BMI < 15 and ANA positive.Conclusions. Anti-NXP2 antibody-positive JDM of Chinese children was characterized by rash and severe muscle weakness. Edema, skin ulcer and severe muscle weakness predicted refractory and poor prognosis. Decreased CD4/CD8 ratio and high SF related with refractory cases, and very low BMI and ANA (+) predicted high risk of gastrointestinal involvement and death.

Background Juvenile dermatomyositis (JDM) is a rare and sometimes fatal disease in children. The anti-NXP2 antibody is one of the most common antibodies and muscle ischaemia associated with NXP2 autoantibodies was a severe subtype of JDM. Further information is needed regarding clinical characteristics and factors associated with poor prognosis. But there are no reports about clinical characteristics and high risk factor of poor prognosis. For the first time, we introduced the clinical characteristics and poor predictors of anti-NXP2 antibody-associated juvenile dermatomyositis in Chinese children. Methods Twenty-six patients with anti-NXP2 antibody-related JDM from 85 JDM Chinese patients were diagnosed from January 2016 to November 2019. Logistic regression was used to analyze the risk factors for refractory cases and mortality. Results The ratio of male to female was 1:1.9. The median age of onset was 4.5 (1–13) years. Twenty-four cases (92.3%) had rash and muscle weakness. Treatments included glucocorticoids, immunosuppressive agents, biological agents (7 cases), plasma exchange, Janus kinase inhibitor (7 cases) and autologous stem cell transplant (1 case). Refractory JDM patients (11/26, 42.3%) were associated with edema, skin ulcer, muscle strength<=grade 3, CD4/CD8 ratio < 1.4 and ferritin > 200μg/ml. Among 6 cases (6/26, 23.1%) with severe gastrointestinal involvement, 5 cases died and 1 case survived after autologous stem cell transplant (ASCT). The risk factors for gastrointestinal involvement and mortality were edema, skin ulcer, severe muscle weakness (dysphagia/ hoarseness/ soft voice), BMI < 15 and ANA positive. Conclusions Edema, skin ulcer and severe muscle weakness predicted refractory disease, GI involvement, and mortality in anti-NXP2 antibody-positive JDM of Chinese children. Decreased CD4/CD8 ratio and high ferritin related with refractory cases, and very low BMI and ANA (+) are probably, associated with gastrointestinal involvement and mortality. Trial registration http://www.chictr.org.cn/showproj.aspx?proj=49846.

Background. Juvenile dermatomyositis (JDM) is a rare and sometimes fatal disease in children. The anti-NXP2 antibody is one of the most common antibodies and muscle ischaemia associated with NXP2 autoantibodies was a severe subtype of JDM.Further information is needed regarding clinical characteristics and factors associated with poor prognosis. But there are no reports about clinical characteristics and high risk factor of poor prognosis. For the first time, we introduced the clinical characteristics and poor predictors of anti-NXP2 antibody-associated juvenile dermatomyositis in Chinese children.Methods. Twenty-six patients with anti-NXP2 antibody-related JDM from 85 JDM Chinese patients were diagnosed from January 2016 to November 2019 . Logistic regression was used to analyze the risk factors for refractory cases and mortality.Results. The ratio of male to female was 1:1.9.. The median age of onset was 4.5 (1-13) years. Twenty-four cases (92.3%) had rash and muscle weakness. Treatments included glucocorticoids, immunosuppressive agents, biological agents (7 cases), plasma exchange, Janus kinase inhibitor (7 cases) and autologous stem cell transplant (1 case). Refractory JDM patients (11/26,42.3%) were associated with edema, skin ulcer, muscle strength<=grade 3, CD4/CD8 ratio <1.4 and ferritin >200ug/ml. Among 6 cases (6/26, 23.1%) with severe gastrointestinal involvement, 5 cases died and 1 case survived after autologous stem cell transplant (ASCT). The risk factors for gastrointestinal involvement and mortality were edema, skin ulcer, severe muscle weakness (dysphagia/ hoarseness/ soft voice), BMI<15 and ANA positive.Conclusions. . Edema, skin ulcer and severe muscle weakness predicted refractory disease, GI involvement, and mortality in anti-NXP2 antibody-positive JDM of Chinese children. Decreased CD4/CD8 ratio and high ferritin related with refractory cases, and very low BMI and ANA (+) are probably, associated with gastrointestinal involvement and mortality .

Objective To evaluate the use of Janus kinase inhibitor (JAKi) in treating JDM and develop cytokine biomarkers of active disease. Methods This study involved a retrospective cohort study that evaluated JAKi in 101 JDM patients as well as a cross-sectional study of cytokines in 128 JDM patients and 30 controls between November 2017 and December 2021 in the Affiliated Children's Hospital of Capital Institute of Pediatrics (China). Results During the median follow-up period of 19 months, 65.5% of the patients improved rashes, and CAT-BM scores decreased. 39.6% of JDM patients eliminated glucocorticoids. Muscle strength was improved in all patients who had abnormal muscle strength before JAKi use. Patients and parents provided positive subjective reviews of JAKi, and no serious adverse events were reported. Potential side effects of JAKi included abnormal leukopenia (14/95) and cough (16/83), which affected over 10% of the JDM patients. In the cytokine analysis, 12/34 cytokines were significantly elevated in active JDM patients. Compared with active JDM patients with multiple phenotypes, active JDM patients with only rashes demonstrated lower cytokine levels. Anti-NXP2-positive active patients had lower cytokine levels compared with those without positive anti-NXP2 antibodies. Among all increased cytokines, IL-1RA changed most dramatically, reaching over 793 times the mean of normal values. We developed a panel composed of 6 cytokines to differentiate active or stable status in our cohort (AUC = 0.8486, P &lt; 0.05). Conclusion The preliminary evidence suggested that JAKi is a relatively safe and effective alternative for JDM patients. Cytokine profiles could well reflect the inflammatory status of JDM patients.

Background: To analyze the effects of ruxolitinib on children with secondary hemophagocytic lymphohistiocytosis (HLH).Methods: Eleven pediatric patients diagnosed with HLH and treated with ruxolitinib (ruxolitinib group: group R) between November 2017 and August 2018 were retrospectively analyzed. Eleven age-matched pediatric patients with HLH undergoing conventional treatment (control group: group C) were also analyzed.Results: In group R, three patients who did not respond to conventional treatment (dexamethasone and etoposide) were treated with Ruxolitinib and their temperature decreased to normal levels. Four patients had normal temperature after conventional treatment, but they had severe organ involvement, including obvious yellowing of the skin, increased liver enzyme levels and neuropsychiatric symptoms, and they were all ameliorated with ruxolitinib treatment. Four patients were relieved with ruxolitinib therapy alone. In group C, the body temperature of eleven patients all decreased to normal levels after conventional treatment. The body temperature of group R patients decreased to normal levels more rapidly than that of group C patients. The hormone dosage in group R was significantly lower than that in group C. Both groups were followed up for 2–2.5 years. No obvious adverse drug reactions of ruxolitinib were observed during treatment and follow-up.Conclusion: Ruxolitinib might be an effective drug in controlling body temperature and reducing inflammation indicators. It might be a potential replacement for hormone therapy for HLH treatment in children, thereby reducing or avoiding hormone-related adverse reactions.